(Xi Shu, Happy Tree, Tree of Life)
Chinese tree with proven anti-cancer properties. The bark, stem and leaves contain camptothecin, an alkaloid effective against leukemia, colon cancer and other tumours, and it blocks the replication of the HIV virus that causes AIDS. Drugs derived from the tree are ringing up sales in excess of $1 billion. In traditional Chinese medicine it is used for the treatment of colds, psoriasis, cancers and leukemia of the liver, gallbladder and stomach. Due to overharvesting in China it is endangered in the wild, but it is now in cultivation in India and Japan. It was introduced to America in 1930s and is growing in Florida and Georgia. The tree reaches 20m/65ft.